Navigation method for a means of transport

ABSTRACT

The present invention relates to a navigation method for a means of transportation, in particular for a vehicle, motor vehicle, ship or aircraft, for navigating from a starting point to a destination, in which a route from the starting point to the destination is specified and the means of transportation or its user is guided along this route. Upon departing from the specified route before reaching the destination, the course traveled at least until re-entering the specified route or reaching the destination is recorded, stored in memory, and upon a later request for a route with the same starting point and destination, the course stored in memory is proposed as the route or the applicable route segment that replaces an originally proposed route segment.

BACKGROUND OF THE INVENTION

The invention relates to a navigation method for a means oftransportation, in particular for a vehicle, motor vehicle, ship oraircraft, for navigating from a starting point to a destination, inwhich a route from the starting point to the destination is specifiedand the means of transportation or its user is guided along this route.

Prior Art

Navigation systems permanently installed in means of transportation,such as motor vehicles, aircraft or ships, direct a driver or operatorof the means of transportation quickly, simply and safely from a currentlocation to a desired destination without the driver or operator of themeans of transportation having to plan a route complicatedly in advanceand acquire appropriate map material. To that end, navigation data basedfor instance on charts, geographic maps, or road maps, are available,stored on something like a digital map base, for instance on CD-ROM. Thenavigation device uses the Global Positioning System (GPS), forinstance, to ascertain an instantaneous location and calculateappropriate navigation instructions that lead to the destination.

In navigating a motor vehicle through a network of roads or streets, forinstance, reproduced by a digital map base stored in memory in thenavigation system, it happens that a driver will select courses or legsthat he prefers, for instance based on his particular knowledge of thelocation, that deviate from a route specified by the navigation system.This often happens with commuters, for instance, who take a regularroute between where they live and where they work. Because suchfamiliarity with places or regular routes is entirely unknown toconventional navigation systems, they keep trying to return the driverto the specified route by instructing him to do so. The driver findsthis unpleasant and annoying, however.

Moreover, from conventional, self-sufficient navigation systems thatcalculate a route based solely on the digital map base, it is impossibleto learn that in actuality such external factors as frequent unexpectedhigh traffic density on certain legs at certain times of day result inaverage speeds different from those stored for that particular partialcourse in the digital map base. For instance, there may in fact befaster routes that the navigation system cannot find in the digital mapbase, because of its fixedly specified average speeds.

SUMMARY OF THE INVENTION

It is the object of the present invention to present an improved methodof the above type which overcomes the aforementioned disadvantages.

To that end, according to the invention it is provided that upondeparting from the specified route before reaching the destination, thecourse traveled at least until re-entering the specified route orreaching the destination is recorded, stored in memory, and upon a laterrequest for a route with the same starting point and destination, thecourse stored in memory is proposed as the route or the applicable routesegment that replaces an originally proposed route segment.

This has the advantage that a navigation system will accordingly learnso-called regular routes that the user or driver of the means oftransportation is quite familiar with and prefers, such as coursescommuters drive daily, and later immediately proposes them as aspecified route or part of a specified route. At the same time, thenavigation system optionally learns new roads or streets, if the driverchooses a course over roads or streets that are not yet stored in adigital map base of the navigation system.

Preferable refinements of the method are described in claims 2-6.

Expediently, upon departing from the specified route before reaching thedestination, a user is asked to input a confirmation as to whether thecourse then traveled is a course to be stored in memory and proposedagain later, or not. The system accordingly receives the informationwhether the departure is an intended or a mistake in deviation from theguided route.

Alternatively, upon departing from the specified route before reachingthe destination, a user is asked to input a confirmation whether thecourse subsequently traveled is to be recorded, or not, and uponre-entering the specified route or reaching the destination, a user isasked to input a confirmation whether the recorded course is to bestored in memory as a preferred course, or not.

In a preferred embodiment, on driving again over a course stored inmemory, the average speeds attained in each case are detected and storedin memory, and the average speeds stored in memory are averaged over apredetermined or user-specified period of time and compared with averagespeeds stored in memory in a digital map base for alternative routes orpartial routes, and an alternative route or partial route is proposed ifthe memorized, averaged average speeds are less, by a predetermined oruser-specifiable amount, for instance of 30%, than the average speedsstored in memory in the digital map base for an alternative route orpartial route.

Also in a method of the above type, it is provided according to theinvention that average speeds attained during the guidance along theroute or along individual course segments are detected, stored inmemory, and compared with average speeds stored in a digital map basefor alternative routes or course segments, and upon a later request fora route with the same starting point and destination, an alternativeroute or course segment is proposed if a detected average speed for aroute or course segment is less by a predetermined value than an averagespeed stored in the digital map base for the corresponding alternativeroute or course segment.

This has the advantage that by constant monitoring of current trafficsituations while a route is being driven, the navigation system can tellfor a future route calculation whether a value for the average speed tobe expected that is stored in memory in the digital map base for theapplicable route or leg is out of date or nonapplicable.

To illuminate incidental statistical deviations in various averagespeeds, the average speeds detected are averaged over a predeterminednumber of traversals of a route before a comparison with average speedsstored in the digital map base is made.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in further detail below in conjunctionwith the drawing. In the sole FIGURE, a specified route is shown alongwith a regular route preferred by a driver as a deviation from thespecified route.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The sole drawing FIGURE illustrates the case, described at the outset,of route guidance from a starting point 10 to a destination 12; solidlines schematically indicate a route 14 specified by a navigation systemon the basis of a digital map base. A circle 16 drawn in dashed linesrepresents a metropolitan area through which the specified route 14leads. A driver who is especially familiar with the place and whosecourse from the starting point 10 to the destination 12 is his dailycourse to work, for instance, has meanwhile learned, for instance fromlong experience and by trying out different courses, that if he deviatesfrom the specified route 14, he attains a higher average speed over analternative leg 18 represented by dashed lines than over the specifiedroute 14. This is because the leg 18 is for instance a “shortcut”familiar only to automobile drivers knowledgeable about the area andcarrying little traffic, or because there are fewer traffic lights, orbetter-timed lights, along that leg 18.

Accordingly, in the course preferred by the driver, the route segment 24is replaced by the alternative leg 18 between a first location 20, wherethe driver leaves the specified route 14, to a second location 22, wherethe driver returns to the specified route. It should be noted at thispoint that the drawing must be understood as merely an example. In anextreme case, the first location 20 can coincide with the starting point10, and the second location 22 can coincide with the destination 12, sothat then the driver discards the entire route 14 specified by thenavigation system.

At the first location 20, the navigation system notes the deviation fromthe guided route. According to the invention, the driver is askedwhether he wants the route subsequently traveled to be recorded. If so,then the navigation system has the information that the driver isintentionally deviating from guidance along the specified route 14 andfor the time being does not attempt to return the driver to thespecified route 14 by giving him directions for it. Instead, thenavigation system records the alternative leg 18, which can also becourses that are not included as roads or streets in the digital mapbase. If the driver does lose his way, however, then by pressing abutton he can re-activate the route guidance and is then guided back tothe specified route 14 by the navigation system.

On reaching the second location 22, the navigation system asks whetherthe recorded leg 18 should be stored in memory as a leg to be proposedas an alternative. If the driver says yes, then in future, upon arequest to specify a route from this starting point 10 to thisdestination 12, the route segment 24 is replaced by the alternative leg18. Roads or streets of the alternative leg 18 that are not stored inthe digital map base are recognized as such by the navigation system andare classified, on the basis of the average speed achieved, as insidecity limits, country road, federal highway, or limited-access highway.As a result, according to the invention, the navigation system can“learn” additional new streets and roads.

On the next trips over the alternative leg 18, the navigation systemthen monitors the average speeds attained, if the driver wishes this. Tothat end, a “commuter” function is for instance provided in thenavigation system, in which the driver must provide the followingadditional inputs:

Limited-access highway: 130 km/h Federal highway: 90 km/h Inside citylimits: 50 km/h Alternative route beyond: −30% Data detection in days: 5

With the parameter “data detection in days”, the driver defines the timeperiod or the number of trips through the alternative leg 18 over whichthe detected average speeds are to be averaged. This largely compensatesfor statistical deviations from the actual attainable average speed. Ifa “0” is input, then only the instantaneously detected average speedsare used, without averaging, so that statistical deviations are nottaken into account. At a value greater than “0”, the navigation systemhas evaluated the incidence of traffic on the leg 18 by way of the valuefor the average speed and compares this value with the expected averagespeed on the route segment 24 in accordance with the data from thedigital map base. If the average speed on the route segment 24 is lessby a predetermined value than that on the alternative leg 18, then thenext time the navigation system again suggests the original route 14 asthe course from the starting point 10 to the destination 12. Thepredetermined value is determined by the driver by way of the parameter“alternative route beyond”. In the above example, a return to theoriginal route segment 24 is made when the average speed on thealternative leg 18 is 30% lower than the average speed to be expected onthe route segment 24 in accordance with the data from the digital mapbase.

In one possible extension of the method of the invention, the driveractivates the “record alternative leg” function at an arbitrary point onhis own, preferably whenever the vehicle location is outside the digitalmap base, or in other words is on a street or road not included in thedigital map base. The recording then begins as soon as the vehiclebegins to move and ends for instance when a course known to thenavigation system is reached, or the driver manually stops therecording. A road width tolerance is expediently chosen generously, tocompensate for measurement variations. On the basis of the travel speed,a rough classification of the road segments is made into categories oflimited-access highway, federal highway, country road, or city traffic.Optionally, hotels, restaurants, sights or the like can also be storedin memory. In an additionally “learning menu” that may be present,additional information, such as one-way streets, stops (places to stayovernight) and so forth are stored in memory.

In alternative embodiment of the invention, the driver does not deviatefrom the specified route 14. Instead, as the specified route 14 isdriven, the navigation system ascertains the average speed attained oncorresponding legs. This is optionally done over several days or severaltrips. Average speeds correspondingly averaged on this basis over thelegs are compared with data on alternative routes from the digital mapbase. For instance, it can happen that the average speed ascertained inpractice for the route segment 24 is lower than for the leg 18considered as an alternative; then in future, this alternative partialcourse 18 will be taken into account in calculating a route from thestarting point 10 to the destination 12. In repeated subsequent tripsalong this alternative leg 18, it is again monitored constantly for itsaverage speed, and if applicable an even better course is found, or ifthe average speed attainable on the alternative leg 18 later dropspermanently, for instance because of such external factors as alteredlight timing or more trips by more and more vehicles, once againpreference is given either to a different leg or to the route segment

What is claimed is:
 1. A navigation method for a means of transportation, in particular for a vehicle, motor vehicle, ship or aircraft, for navigating from a starting point to a destination, in which a route from the starting point to the destination is specified and the means of transportation or its user is guided along this route, characterized in that upon departing from the specified route before reaching the destination, the course traveled at least until re-entering the specified route or reaching the destination is recorded, stored in memory, and upon a later request for a route with the same starting point and destination, the course stored in memory is proposed as the route or the applicable route segment that replaces an originally proposed route segment.
 2. The method of claim 1, characterized in that upon departing from the specified route before reaching the destination, a user is asked to input a confirmation as to whether the course then traveled is a course to be stored in memory and proposed again later, or not.
 3. The method of claim 1, characterized in that upon departing from the specified route before reaching the destination, a user is asked to input a confirmation whether the course subsequently traveled is to be recorded, or not.
 4. The method of claim 1, characterized in that upon re-entering the specified route or reaching the destination, a user is asked to input a confirmation whether the recorded course is to be stored in memory as a preferred course, or not.
 5. The method of claim 1, characterized in that while driving or on driving again over a course stored in memory, the average speeds attained in each case are detected and stored in memory.
 6. The method of claim 5, characterized in that the average speeds stored in memory are averaged over a predetermined or user-specified period of time and compared with average speeds stored in memory in a digital map base for alternative routes or partial routes, and an alternative route or partial route is proposed if the memorized and averaged average speeds are less, by a predetermined or user-specifiable amount than the average speeds stored in memory in the digital map base for an alternative route or partial route.
 7. A navigation method for a means of transportation, in particular for a vehicle, motor vehicle, ship or aircraft, for navigating from a starting point to a destination, in which a route from the starting point to the destination is specified and the means of transportation or its user is guided along this route, characterized in that average speeds attained during the guidance along the route or along individual course segments are detected, stored in memory, and compared with average speeds stored in a digital map base for alternative routes or course segments, and upon a later request for a route with the same starting point and destination, an alternative route or course segment is proposed if a detected average speed for a route or course segment is less by a predetermined value than an average speed stored in the digital map base for the corresponding alternative route or course segment.
 8. The method of claim 7, characterized in that the average speeds detected are averaged over a predetermined number of traversals of a route before a comparison with average speeds stored in the digital map base is made. 